One Last Thing
by FollowMeAround
Summary: The younger sister of one of Reid's best friends is targeted by a serial killer. Reid is assigned to protect her, and he falls for her. But things get out of control quickly. Reid/OC
1. Chapter 1

**Of course, all rights to their respective owners. I only own the UnSub, the Amstell-Fielding family, and other people I make up. **

"I hate Valentine's Day!" a young redhead said to herself as she walked into her apartment. The young woman had a good reason to hate the particular day. Her longtime boyfriend broke up with her the day before yesterday and she recently caught him on a date with one of her former friends.

She sighed as she tried to get in contact with her family overseas. Her father was a prominent chemist with a very high IQ. He surprised his family with a vacation to Italy. She kindly refused to go since she wanted to spend time with her boyfriend.

"I'm such a bonehead," she said to herself, "I could be having the time of my life in Italy but no, here I am alone, in the middle a snowstorm!"

The woman lived in the Lake Tahoe area in Northern California. It had been snowing recently and it wasn't helping that she couldn't even leave her town for a day or two.

She poured herself a glass of wine and sat down as she watched television, drowning her sorrows. She was about to order a movie when the power went out.

"Fuck my life!" she yelled out loud as she went to turn on the small generator. It didn't work either. So she lit some candles and covered herself in a blanket and dozed off to sleep.

She woke up with ties on her hands and legs and duck tape around her mouth. She wasn't sure if she was still in her apartment or if she was moved.

"Kym, isn't it?" she heard a voice come out of the darkness. "Kym Barnes? 25 years old, recently single, family out of the country?" it continued.

She frantically tried to move her head around to see the man.

Kym Barnes did not see the gun pointed to her head.

It fired.

"Did you know that Valentine's Day celebrates love and affection between intimate companions? The day is named after one or more early Christian martyrs named Valentine and was established by Pope Gelasius I in 500 AD." Reid said, rambling on as usual.

Everyone turned around and gave Reid the face. The face is usually an expression of "thanks Reid, but I really did not want to know that." He's gotten used to it.

They were called in because a victim of a suspected serial killer came in.

"25-year-old Kym Barnes was found shot in the head at 11:00 AM pacific time," Hotch said, "it seems that she is a victim of the same killer, which the press is now calling The Holiday Killer."

"What is that paper in her hand?" Morgan asked noticing a pink paper in the victim's hands.

"It's a Valentine's Day card, something people give to each other today," Hotch continued.

The Holiday Killer was true to his namesake, killing a woman every holiday. His first victim was Janet Mars, who was killed on Christmas Day, and then it was Ruth Scodelario, killed on New Year's Day. Kym Barnes was the latest victim.

"Does anyone have any idea what connects the three women? They died different ways, Janet was poisoned, Ruth was stabbed, and Kym was shot," Hotch asked hoping for a connection.

Reid spoke up, "I was investigating their family history and they have only a couple of things in common. Their fathers were all geniuses, their family was out of the area during the time, and they all live in Northern California."

Janet's father was a famous professor who was in Hawaii at the time, Ruth's father was a famous doctor in the medical field and was in South America and Kym's father was a chemist who was in Italy.

Garcia came up on the screen ready to find any information on the killer.

"Baby Girl, can you find men in the Northern California area who have children in the age range of 21 to 30, and have an IQ of over 165?" Morgan asked.

"Well Chocolate Adonis, since you were so particular in your search, I've found the perfect match. I think Boy Genius is going to be very excited for this one," Garcia answered with a knowing glance at Reid. He blushed a little since he could hardly contain his excitement when he first heard that he was going to interview his idols, the Doctors Mars and Scodelario. But Hotch now knew better and now Morgan was going to interview Dr. Barnes this time around.

"Doctor Peter Amstell has an IQ of 197, the highest out of the four doctors. His wife isn't too shabby either; Doctor Victoria Fielding has an IQ of 175. They have four children, although daughter Amelia passed when she was nineteen. They now have eighteen year old son Jethro, and twins Anthony and Adelaide. They recently went on a two month vacation to rural parts of Asia. Oh and they left behind their twenty four year old daughter Adelaide," Garcia said in what seemed to be one long breath.

"Is it possible that Adelaide might be the next victim?" Emily asked.

"Well the next major holiday is St. Patrick's Day, so we have a lot of time," Hotch said, "but that doesn't mean that the killer won't strike before, so we better get over there."

"I'm sending you the address, go find the skeeze of the year, guys! Garcia out!" Garcia said sighing as she looked at the medical records of the young and beautiful Adelaide. Poor girl had three suicide attempts in the past ten years. One shortly after her sister's accident, then two years later, and the last attempt was three years ago. She was clinically depressed and only got off anti-depressants a year ago. And on top of that, she was now a potential murder victim. Garcia could only hope that the news wouldn't damage her already fragile mind.

"Does anyone know how Adelaide looks like?" Morgan asked as he sat down.

Almost immediately, JJ handed everyone a picture of the woman in question. Adelaide Amstell was beautiful, with dark chestnut hair and the saddest blue eyes. Even though she was smiling in the photo, there was a hint of sadness in her smile.

"Amelia Amstell, Doctor Amelia Amstell, of course!" Prentiss said, seemingly out of nowhere.

"But we're not talking about Amelia, we're talking about Adelaide, Prentiss," Morgan said, slightly confused.

Prentiss reached into her bag and took out a book. "Her family published her diary, it was written the year she died. It's brilliant, she was such a genius, but she had a normal teenage quality about her. She didn't seem to like being a genius; she wanted to be in fashion. Amelia didn't like meeting other geniuses, oh, and there's even a part about Reid!" Prentiss said, trying to find the specific date.

"No way, Reid you met her?" Morgan said, now scooting in closer to see the book. He was joined by JJ, Rossi, and even Hotch.

Of course, Reid turned red as a tomato, and tried to stammer out an explanation.

"W-Well… s-she w-was a genius too, a-and we always got p-paired up s-since we w-were so close in age. S-She was nineteen and I was t-twenty, I s-swear nothing h-happened. It was simply p-platonic," Reid said, barely audible.

"Ah, I found it!" Prentiss said, clearing her throat.

_July 13_

_Dear Old Friend,_

_ Yesterday was a pleasant evening. Oh! I forgot to tell you didn't I? Please forgive me, dear friend. I was forced (by Mother and Father, no less) to go to the Annual Young Genius Summer Dinner. Of course, I had to go because Jethro was with Grandmamma in Scotland. Anthony was studying with an old artist in Italy. And Addie was sick again, in the hospital. I hope she's okay, the greater power knows that she needs the hope._

_ As I was saying when I was in Los Angeles for the dinner, I encountered my old friend Spencer Reid. He's twenty years old and he's already a doctor. He has an IQ of 187 and I tease him mercilessly because my IQ is only a point higher than his. But it's all in good fun. He's a bit awkward (which male genius isn't?) but it's a good awkward. Most people think we're dating but I don't see him that way. Way too nerdy for my taste. :D _

"That's all she mentions about you, minus a picture," Prentiss said, holding up the book so everyone could see. It was small taken by a professional camera. Reid looked awkward in a tuxedo that looked way too big for him. Amelia was wearing gorgeous strapless blue dress and she had her arms around Spencer. He couldn't look more nervous.

"Aw, baby Reid," JJ said, looking at Reid's cherry red face.

"What's wrong, Spencer, why are you being a sad tomato?" Morgan said, poking Reid's face.

Reid swatted away Morgan's hand and looked out at the window. "Okay then we'll leave you alone Boy Genius," Morgan said.

"Revisiting memory lane, isn't he?" Rossi said, sitting down back in his seat. "Hasn't thought about Dr. Amelia Amstell since her death," he continued, "it's all coming back to him now."

It was true that Reid hadn't thought of Amy since her death eight years ago. He blocked her out of his thoughts, since he thought himself responsible for her untimely passing.

He was living in San Francisco at the time, and Amy was living in Berkeley. He was having the nightmares again, and he needed comfort from a friend. She was his only friend.

The memory came back to him suddenly, the last conversation he had with her.

"_Amy, I can't sleep," Spencer said, "The nightmares are worse than ever."_

"_Spence, you say the word and I'll be there," Amy said yawning a bit; it was a little bit after midnight._

_Reid sighed and asked her to come over for a late night Star Trek marathon. Amy agreed and said she'd be there in half an hour. _

"_So I'll see you then," Spencer said. _Reid was now fighting back tears.

"_Of course Spencer Reid, I'll always be there for you, bye," Amy hung up. _

_Amelia Amstell didn't come in half an hour. After nearly two hours of waiting and not getting a call from Amy, Spencer decided to spend the night at her apartment. _

_He was driving in his car when he saw a major car pileup. He groaned, thinking that this would set him back at least another hour, even though it was pushing two in the morning. When it was his finally his turn to pass the wreckage, he didn't see a pale hand sticking out, belonging to a pretty redhead._

_Doctor Amelia Jane Amstell was dead at nineteen, on her way to comfort her friend by staying up all night watching old episodes of Star Trek._

Reid tried to block out the memories that were flooding in. Such as Mrs. Amstell's cry when she first heard the news. Or the blank, emotionless stare of Adelaide.

He last saw the Amstell family at Amy's funeral. Three days later, Adelaide tried to commit suicide for the first time. He never understood her reason for it. Her parents just lost their child and she went off, trying to remove herself from the world. Reid had heard of her depression and he hoped that she wouldn't have another breakdown.

"Did you love her?" Morgan asked, noticing the grief on the young man's face.

"Romantically? No, she was my only friend. For a lot of the kid geniuses, she was the only girl they felt comfortable with. She meant a lot to people," Reid answered, barely audible.

"So she went to a lot of proms, didn't she?" Morgan asked, smiling a little.

Reid smiled, "She went to at least 20 different proms. I don't know how she did it."

The plane was now landing in San Francisco. After her funeral, Reid promised himself that he wouldn't come back. But as he stepped off the jet, he couldn't help but see Amy everywhere. They had so many memories in this city. But one stood out to him.

"_I was talking to my pen pal Rinko when she asked me to write a fake letter to my friends and family. Just like an experiment. So I wrote you one," Amy said, handing Reid a letter._

_Dear Spencer Reid,_

_ I'm writing this because I am now deceased. You are one of my closes t friends, and don't you dare forget about me (as John Hughes would say). Because I died an untimely death, I leave you with a mission. (Oooh! A message from beyond the grave!) My family will fall apart after my death, but they will, after hard work, get better. I know that you will become something big Spencer and I know that Addie will take my death the hardest. No one can help her. Not Anthony, Father, Mother, Jethro, Grandmamma, or her friends from school. You can help her Spence, I know you can. So if the time comes, when I'm dead and Addie needs more than ever, you've got to fix and protect her. It'll be hard, but who knows? Maybe you'll fall in love…_

_Love,_

_Doctor Amelia Jane Amstell_

_After he read the letter he pushed it off as nonsense. Amy wasn't going to die anytime soon, right?_

Reid was going to do everything in his power to protect Adelaide from the murderer. Only one more thing for Amy.


	2. Chapter 2

**Again, I only own the UnSub, the Amstell-Fielding family and other OCs.**

"Morgan, Rossi, and JJ, you are going to Lake Tahoe to investigate and interview the Barnes family," Hotch said, getting off the phone.

"Prentiss, Reid, and I will try to warn Adelaide. She lives in Berkeley, in the Panoramic Hill neighborhood," he continued and the team went their separate ways.

As they were walking away Reid said, "Something tells me that she won't be at her home. What about checking her parents' house and her brother Anthony's flat?"

"If she isn't there, we will be visiting those houses. She might be house sitting them," Hotch continued.

"Okay I know the family is wealthy, but wow! You must be raking in a lot to pay your daughter's rent," Prentiss said, eyeing the scenery outside the SUV's window.

"And not only Adelaide's rent, but theirs, Anthony's, their children's education, clothes, food, family trips, and miscellaneous stuff, yeah it adds up to quite a lot," Reid said, not affected by the abundant wealth in this neighborhood. He's visited Mr. and Mrs. Amstell's home before, many years ago.

After getting a bit confused (since the neighborhood was in the infamous hills of Berkeley) they found her house.

"Oh, this is the Ferguson-Stielberg house! They died a couple of years ago, plane crash. Nice people," Reid said walking up to stairs leading up to the front door. He ignored Prentiss and Hotch's stares.

"Adelaide Amstell! FBI here!" Hotch said knocking a couple of times. Ten minutes passed and still no answer. They called her house and cell phone, still no answer.

"Maybe she's in the backyard, it's a nice day today," Prentiss said after a while.

"The door is locked. We can't go around it," Reid said sitting down on a small boulder.

"Okay Reid, if you can stop being Dora the Explorer, maybe we can find a way to get in," Prentiss said shivering. Reid glared at her and Hotch barely concealed a small grin.

After a few more minutes of standing around and knocking on the door Emily Prentiss had a plan.

Morgan, JJ, and Rossi finally reached the Barnes family compound. It was a large place, with its own hill for skiing and snowboarding. A large man greeted him at the house's entrance.

"I'm SSA Derek Morgan, this is SSA David Rossi, and this is SSA Jennifer Jareau," Morgan said shaking his hand.

"I'm Simon Barnes, Kym's father," he said, "I've seen Jennifer on television when she talked about dear Ruth and Janet, I was their godfather."

"Yes sir, please call me JJ, I'm in charge of the media and I'll be organizing a conference concerning the death of your daughter," JJ said.

He nodded and turned to Rossi, "and of course, I know David," he gave Rossi a pat on the back, "we go way back."

Rossi smiled and nodded at his old friend Simon Barnes.

He signaled them to enter the house.

A small woman came out from the kitchen. She had mousy brown hair, and was wearing a thick red sweater, and she had mousy brown hair.

Her voice matched her hair, "hello, I'm Kathleen, welcome to our home," while she was introducing herself, her younger daughter came down.

"Oh, and this is my youngest, Samantha," Samantha politely said hello and sat down in her living room.

"She's feeling sadder than us, see, the reason we went to Italy was for her 21st birthday, so she feels responsible for her death," Kathleen said, then she asked them if they wanted coffee.

The three agents were a bit surprised how well they were taking the situation.

"Can we interview Mr. Barnes alone?" Morgan asked Kathleen and Samantha. They both agreed and Kathleen went back to the kitchen and Samantha went to her room.

"You said that she was found with a card in her hand, what did it say?" Simon asked the team.

"Well it didn't say anything, it just had a sticker of a leprechaun with a pot of gold on it," JJ responded.

"Does that mean if you don't catch him, he'll strike again on St. Patrick's Day?" Simon said.

JJ nodded her head and they thanked him. They were about to leave the house when Simon stopped them.

"Is Adelaide next?" Simon asked carefully.

"Excuse me?"

"Adelaide Amstell, she lives in Berkeley, twenty four years old, her family is in Asia, and her father is a genius. Is she the next potential victim?"

"Well, sir, we have good reason to suspect that Adelaide could be a potential victim," JJ said slowly.

"Are you good at doing your job?"

"We try the best we can, Mr. Barnes."

"Good because I do not want to bury another one of my goddaughters."

With that, he closed the door and the three agents went off.

"Okay Reid, are you ready?" Hotch asked putting out his two hands.

"I have no other choice do I?" Reid replied.

"It's not even that high up, Reid just do it!" Prentiss said, getting impatient.

Reid stepped on Hotch's hands and was lifted up over the iron gate. Although his pant leg got caught, nothing major happened. Which is what Reid thought was going to happen, and he was against all of this in the first place. He said it was an invasion of privacy.

But they made him do it anyway.

Reid got over the fence and opened the garden door from the inside.

They tried knocking on the back door when they discovered it was open.

The team cautiously entered the house.

"Adelaide Amstell? It's the FBI. Adelaide?" Hotch said looking around the home.

"I'm going to go check the rooms," Prentiss said.

After a couple of minutes, she returned, not finding Adelaide anywhere in the house.

"We should call her parents house and Anthony's house, just in case," Prentiss said taking out a phone.

"Whoa, what happened to her phone?" Reid said. He picked up a destroyed iPhone that looked like it was smashed by a hammer.

"Do you think she did it?" Prentiss said, moving closer to the phone.

"Well, we need to talk to her in order to find out, Emily did you call the homes yet?" Hotch asked.

"I'm on it."

There was no answer from either of the houses.

"We're going to split up, Prentiss goes to Anthony's house, I'll go to Mr. and Mrs. Amstell's house, and Reid stays here," Hotch said.

It was getting late and Reid was all by himself inside Adelaide's house. He was getting a bit bored so he started snooping around the house.

One thing caught his attention. It was an interactive mirror. When he first walked by it, it was activated by his movement. The mirror showed the company's logo and Reid just stood there for a while, a bit surprised.

Reid walked up to the mirror and cautiously touched it with his finger. His finger made a splat of green color on the mirror. After toying around and drawing a rather impressive stick figure, Reid was looking at other options.

"No way," Reid said, his eyes lighting up. He had always wanted to play Space Invaders on a large touch screen.

Spencer was beating the high score when she came in.

"Spencer Reid?" she said looking at him strangely.

"Yeah, that's me, hold on for one second," he was almost there…

"This is great, I come home, see someone I haven't seen in years, and he's smudging up my mirror," she said to herself.

"New high score! Congratulations!" the voice in the mirror said.

"Yes, yes!" Spencer said, jumping up and down and flailing his arms everywhere.

Then he noticed the quizzical look of the woman standing behind him. She hadn't grown much since the last time he saw her. Her sea blue eyes were wide open and she had a small smile on her face.

"Adelaide! Where have you been?" Spencer said, giving her an awkward hug.

"I was at an opening ceremonies party for the Olympics."

"But wasn't that four days ago?"

"Yeah, I know."

"Should I not ask?"

"Yeah you shouldn't ask. And anyways, why in the hell are you in my house, playing on my mirror?"

"Oh yeah, about that. I'm a FBI agent and um, I should call my boss to explain this to you."

"You go do that, FBI agent; I'm going to take a shower."

Spencer got out his phone and called Hotch and Prentiss.

They arrived twenty minutes later drenched in rain.

"We got caught in the rain, where is she?" Hotch asked.

"She told me she was going to take a shower."

"Where was she?"

"At an Olympic opening ceremonies party. That was four days ago."

"Oh, wow."

"Hello. I'm Adelaide Amstell," she said, completely out of nowhere.

"Hello Ms. Amstell, I'm SSA Aaron Hotchner and this is SSA Emily Prentiss. I've seen that you are already familiar with Dr. Reid."

"Of course, he's an old family friend. One that I haven't seen in years, but still a friend."

"Can we talk and sit for a moment? We'd like to tell you something," Hotch said.

"Yes, we can sit in the family room."

They all sat down.

Hotch began, "are you familiar with Kym Barnes?"

"Our families were friends. I didn't really like her, but I can't change someone's personality," Adelaide said, looking out the window with interest.

"Did you come to tell me that she's dead?" she spoke in a light voice. You could hear small traces of a long gone Scottish accent.

"How did you find that out? Did someone call you, perhaps the Barnes family?" Hotch asked.

"With all due respect Agent Hotchner-"

"Call me Hotch."

"With all due respect Hotch, I'm not an idiot." Adelaide was still staring at the moon outside the window.

"I never said that you were Ms. Amstell-"

"Adelaide."

"Adelaide, how did you find out about Kym's death?"

"As I said before, I'm not an idiot. It does help that I'm friends with the Scodelario, Mars, and Barnes family and that I was told about the details of Janet and Ruth's murders. But I know that Kym was killed by the same person."

Adelaide looked away from the window, finally facing the three agents.

After a deep breath she said, "You're going to tell me that I'm next."


End file.
